This was a German operation against the partisan forces of Marshal Josip Broz Tito in the northern part of the Istrian region of German-occupied Yugoslavia (26 April/6 May 1944).

The undertaking involved some 25,000 men of Generalleutnant Harry Hoppe’s 278^th Division, Generalleutnant Wilhelm von Hösslin’s 188^th Reserve-Gebirgsdivision, SS Karstjägerbataillon, 1/SS Polizeiregiment 'Bozen' and a number of garrison units in the area of Kastav, Cicarija, Podgrad and Brkina against the 1^st Istrian 'Vladimir Gortan' Brigade, 1^st 'Istria' Partisan Detachment and 'Slovene Istria' Partisan Detachment.